* Copyright (c) 2011 Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the GNU Lesser Public License v2.1
* which accompanies this distribution, and is available at
* Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany - initial API and implementation
DefaultMutableTreeNode that override
Because when we build the directory tree, we use lazy load, we want all the files looks like
a directroy, so the isLeaf() method return false
for more information.